Magnetic sensors are widely applied to modern industry and electronic products to sense magnetic field intensity to measure physical parameters such as current, position and direction. In the prior art, there are many different types of sensors which are used for measuring magnetic fields and other parameters, such as magnetic sensors using Hall elements, Anisotropic Magnetoresistance (AMR) elements, or Giant Magnetoresistance (GMR) elements as sense elements.
Although Hall magnetic sensors are applicable to high-intensity magnetic fields, the Hall magnetic sensors have very low sensitivity, great power consumption and poor linearity. Although AMR magnetic sensors are more sensitive than the Hall sensors, the AMR magnetic sensors are complex in manufacturing process and are high in power consumption. Although GMR magnetic sensors have higher sensitivity than the Hall magnetic sensors, the linearity range thereof is slightly low.
Tunneling magnetoresistive (TMR) magnetic sensors are novel magnetoresistance effect sensors which have been industrially applied in recent years, utilize a tunneling magnetoresistance effect of a magnetic multilayer film material to sense magnetic fields, and have higher sensitivity, lower power consumption, better linearity and wider working range than Hall magnetic sensors, AMR magnetic sensors, and GMR magnetic sensors.
Compared with a single-resistor, or a referenced bridge magnetic sensor, push-pull bridge magnetic sensors have higher sensitivity and lower offset, and simultaneously have a temperature compensation function, thus can suppress the influence of temperature drift.
However, the sensitivity of the existing push-pull bridge magnetic sensors is not high enough and the noise is not small enough.